some main file possibilities

sam3s_example/mains/spi.c

@@ -0,0 +1,77 @@
+#include "board.h"
+#include "spi.h"
+#include "pio.h"
+#include "pmc.h"
+#include "usart.h"
+
+#define BUFFER_SIZE         20
+
+/** Pins to configure for the application.*/
+const Pin pins[] = { BOARD_PIN_USART_RXD,
+                     BOARD_PIN_USART_TXD
+//                     PIN_USART1_SCK,
+//                     BOARD_PIN_USART_RTS,
+//                     BOARD_PIN_USART_CTS,
+//                    PINS_SPI,
+//                    PIN_SPI_NPCS0_PA11
+                    };
+
+char Buffer[BUFFER_SIZE] = "Hello World";
+/**
+ * \brief Configures USART in synchronous mode,8N1
+ *  * \param mode 1 for  master, 0 for slave
+ *   */
+static void _ConfigureUsart(uint32_t freq )
+{
+    uint32_t mode;
+/* MASTER; mode  = US_MR_USART_MODE_NORMAL
+                    | US_MR_USCLKS_MCK
+                    | US_MR_CHMODE_NORMAL 
+                    | US_MR_CLKO
+                    | US_MR_SYNC    // FIXME: sync or not sync? 
+                    | US_MR_MSBF
+                    | US_MR_CHRL_8_BIT
+                    | US_MR_NBSTOP_1_BIT
+                    | US_MR_PAR_NO ;
+*/
+
+
+// Slave mode:
+        mode = US_MR_USART_MODE_NORMAL   
+//                | US_MR_USCLKS_SCK    // we don't have serial clock, do we?
+                | US_MR_CHMODE_NORMAL
+//                | US_MR_SYNC 
+                | US_MR_MSBF
+                | US_MR_CHRL_8_BIT 
+                | US_MR_NBSTOP_1_BIT
+                | US_MR_PAR_NO;
+    
+    /* Enable the peripheral clock in the PMC */
+    PMC_EnablePeripheral( BOARD_ID_USART ) ;
+
+    /* Configure the USART in the desired mode @USART_SPI_CLK bauds*/
+    USART_Configure( BOARD_USART_BASE, mode, freq, BOARD_MCK ) ;
+
+    /* enable USART1 interrupt */ 
+//    NVIC_EnableIRQ( USART1_IRQn ) ;
+
+    /* Enable receiver & transmitter */
+    USART_SetTransmitterEnabled( BOARD_USART_BASE, 1 ) ;
+    USART_SetReceiverEnabled( BOARD_USART_BASE, 1 ) ;
+}
+
+int main() {
+    /*  Configure pins */
+    PIO_Configure( pins, PIO_LISTSIZE( pins ) ) ;
+
+    _ConfigureUsart( 1000000UL);
+
+    USART_WriteBuffer(BOARD_USART_BASE, Buffer, BUFFER_SIZE);
+
+// FIXME: do we need to call USARTEnable?
+
+
+// FIXME: do we need to call USARTDisable?
+
+    return 0;
+}